Pressure-controlling device for conveyer tubes



Aug. 17,1926.

J. G. MACLAREN PRESSURE CONTROLLING DEVICE FOR CONVEYER TUBES Filed Feb. 25, 1922 2 Sheets-Sheet amoemtoz 51 Man HREN Aug. 17 1926.

J. G. MACLAREN PRESSURE CONTROLLING DEVICE FOR CONVEYEVQR TUBES Filed Feb. 25, 1922 2 Shets-Shee.

allfllllldzrdvwvvg 'forms of the invent Patented Aug. 17, 1926.

UNITED STATES PATEN PRESSURE-CON TROLLIN G DEVICE FOR CON VEYER TUBES.

Application filed February 23, 1922. Serial No. 538,687.

This invention relates in general to pneuof the casing,

said wall separating the chammatic despatch apparatus and more parber 22 which communicates with the transtieularly to vmeans for automatically conmission tube 5 from a chamber which comtrolling the flow of air throu h the tubes municates with the vacuum drum 6. The in accordance with the work to e done. use of two separate valvemembers on the he invention includes a controlling valve same valve rod 1 having directly connected operating means subject to pressure conditions inside a transit tube, the valve being moved to a position when the tube is unoccupied by a carrier to permit only a relatively restricted flow of air through the tube but opening, upon the normally the weight of the valve structure change in pressure conditlons produced in holds the valve memb the tube by the insertion of a carrie t to permit an increased flow of air through the tube to bring about the propulsion of the carrier. 1 r

The invention also includes a balanced valve structure operable by slight changes in pressure in the tube and being correspondingly sensitive whereby the increase in flow 'of air to the degree needed for propulsion is brought about in a minimum time interval and substantially instantaneously with the insertion of a carrier in the tube while the discharge of the carrier likewise results in instantaneous restoration of flow conditions to normal, thus avoiding unduly prolonged air flow with consequent waste of power.

In the drawings,

5 produces a Well-defined condition of balance, as will be clear, because of the oppositely acting and balancing pressures exerted on the separate members.

The valve rod 15 is mounted to slide longitudinally in bearing brackets 16 and 17 and e 5 V A by-pass or restricted opening 20 is provided in the wall 8 permitting a constantly effective slow leak from the chamber 22 to the chamber 21 which communicates with the suction drum.

In operation assu in the transit trans sure in the tub ming that no carrier is mlssion tube 5, the prese and chamber 22, is but in which twoalternative ion are illustrated tical sectional view of a pneumatic conveyer tube controlling device embodying the invention.

Figure 2 is a view similar to F showing an alternative f tion.

- Referring to the drawi ransmission tube is she which and an air moving be a header or drum co able exhausting device, or casing 7. It will be seen that a relatively ow pressure established in the drum 6 will produce a flowof air in the tube 5. This flow is regulated and controlled by a main valve 10 disposed within the housing or casing 7 and this controlling device forms the subject matter of the Figure l is a ver nearly equal the diaphragm and valve igure 1 orm of the inven- O the opening 2l i to take place. Gravity may be valve seating operation by a differential eifect in the valve structure produced by forming the valve head ll-with a somewhat greater area than the area of the other valve head 12.

When a carr station into th immediately d rier and the li main valve is by the liftin s thus normally permitted ngs one end of a aided in the wn at ,5, between means 6 which may nnected to any suitis a hollow housing ier is inserted at any e transit tube 5 rops in advance ght and substantia practically instantly operated g action of the diaphragm which is pressed upwardly by atmosphere acting on its lower face. his immediate opening of the valve is followed by a rush of air into the exhaust drum and results in the propulsion of the carrier through the no sending the pressure of the carlly balanced tube. The emergence of the carrier from the tube at an exit point is immediately followed by the snapping of the valve structure to closed position, this action apparently being assisted by a reaction or momentary surge of air through the tubeand into the chamber 22 resul ing in a momentary rise of pressure in t e chamber above the pressure of the atmosphere.

In Figure 2 of the drawing there is shown a modified form of the invention in which a spring 25 is employed r'or moving the valves to their seats. By the use of the spring gravity is not made use of in the operation of the valve and the structure can be placed in any position with relation to the horizontal.

The closing of the valve to cut off the fiow of air through the system is thus determined directly by the delivery of the carrier from the transmission tube and is wholly independent of any timing device so that waste of power is substantially eliminated.

What I claim is 1. Power control apparatus for a pneumatic despatch system having a transmission tube comprising a casing having a chamber therein, a main valve controlling an orifice in a wall of .the casing, a minimum flow of air from one side of said wall to the other normally being permitted, and a movable actuator connected vto the valve, said actuator always being freely exposed upon one side to the atmosphere an at its other side to the pressure existing in said chamber, said actuator initiating opening of the main valve upon the occurrence of conditions in the transmission tube arising from the introduction of a carrier therein and immediately initiating closure of the main valve upon the occurrence of conditions in the transmission tube arising from discharge of the carrier from the latter.'

2. Power control apparatus for a pneumatic despatch system having a transmission tube comprlsing a casing having a chamber therein, a normally closed valve controlling an orifice in a wall of said chamber, a minimum flow of air from one sideto the other of the valve normally being permitted, and a movable actuator connected to the valve, said actuator being always freely exposed upon one side to atmospheric pressure and at its other to the pressure existing in said chamber, said'actuatorinitiating opening of the main valve immediately upon introduction of a carrier into the transmission tube and closing of said valve immediately upon discharge of the carrier from thetube.

3.. Power control apparatus for apneumatic despatch system having a transmis sion tube, said apparatus comprising a casing connected to the transmission tube, said matic despatch system ing a casing,

casing havin valve control lng an orifice in a wall of said chamber, a minimum flow of air from one side of said wall to the other normally being permitted, a diaphragm freely exposed at one side to atmospheric pressure and at its other side to the pressure in said chamber, and means connecting the diaphragm to the valve, the diaphragm being directly responsive to conditions arising in said chamber upon introduction of a carrier into the transmission tube and delivery of a carrier therefrom respectively to open the valve and to permit its closure-immediately upon the occurrence of such respective conditions. 4:. Power control apparatus for a pneumatic despatch system of the vacuum minimum-flow type having a transmission tube and exhaust means, said apparatus comprising a casing, a partition dividing the easing into an inlet chamber which always freely communicates with the transmission tube and an outlet chamber always in full communication with the exhaust means, said partition having a valve aperture therein, a balanced valve device governing the flow of carrier impelling air current from the in let to the outlet chamber, a minimum flow of air from the inlet to the outlet chamber being permitted at all times, and a single element connected to the valve device for moving the latter, said element itself being directly responsive alternately to pressure and to the velocity effect of air flow in the inlet chamber to open the valve device and to permit it to close, said valve moving means being at all times exposed on one side to atmosphere pressure and at its other side to transmission tube pressure and opening the valve device upon introduction of a carrier into the tube and permitting it to close upon delivery of the carrier from the tube. 5. Power control apparatus for a pneuof the vacuum minimum-flow type having a transmission tube and exhaust means, said apparatus comprisa partition dividing the easing into an inlet chamber which always freely communicates with the transmission tub and an outlet chamber always in full communication with the exhaust means, said partition having a valve a movable valve member or closing said aperture, a minimum flow of air from the inlet chamber to the outlet chamber being permitted when the valve is in closed position, a pneumatic connected member, one sideof the pneumatic being exposed at all times to the pressure in the inlet chamber and the other side of the pneumatic-always being expo to atmospheric pressure, the pneumatic responding directly to the reduction in pressure in the inlet chamber resulting from the reduction in the flow due to introa chamber therein, a main erture therein, a

to the valve.

duction of a carrier into the tube and by ways communicating with the outlet, said such response opening the valve to permit partition having coaxial valve apertures in carrier impelling air flow through the valve its arallel walls, a balanced valve having aperture, the pneumatic also responding; hea s cooperating with the respective aper- 25 dlrectlyto the sudden rush of air through tures, means providing for a minimum flow the inlet chamber of the casing incident of air from the inlet to the outlet chamber to delivery of the last carrier from thestube at all times, a stem for the valve, guides for and by such response permitting the valve the stem, a diaphragm forming a movable member to return toclosed ition thereby side wall for the inlet chamber, the inner 30 to shut ofi the carrier impe- 'ng air flow. surface of the diaphragm being exposed at 6. Power control apparatus for a pneuall times to transmission tube pressure, the matic despatchs stem of the vacuum miniend of the stem projecting through the cenmum flow type liaving a transmission tube ter of the diaphragm, and means connecting and an exhauster, said apparatus compristhe diaphragm to the stem, the casing com- 35 ing a casing having an'lnlet opening at one prising a dished cover plate protecting the side and an outlet opening at the opposite outer side of the diaphragm, said plate havside, the inlet communicating with the trans ing a central opening for the passage'of the mission tube and the outlet with the ex-v valve stem and to permit full access of athauster, a U-shaped partition within the mospheric air to the outer face of the dia- 4 casing separating a chamber always commuphragm,

mcating with the inlet from a chamber al- JAMES G. MACLAREN. 

